kt333 wont run 133fsb, works fine 100

i've had my kt333 dragon lite for about a year and a half, maybe more, maybe less - not sure. anyway i got a new cooling kit recently in hopes that i could decently overclock my amd 1900+ (which ran FINE at 133 fsb the entire time i had it). i got to about 140 fsb without raising the voltage. then i tried 143 (raised voltage slightly, by .05), it posted, but locked up in the bios - temps are fine. from that point on i could never get my board running back at 133... whenever i reset cmos i could run fine at the 100fsb (1200 mhz), but if i changed it back to 133 it either locks up at the very first bios post, or it wont even initialize the display. i know the processor isnt dead, i tested it on my friend's comp - he has same setup. i've tried new mobo battery, switching out powersupply, even new ram. i've also flashed the bios twice. any ideas as to what could be causing this? any guesses or solutions from people with similar problems would be GREATLY appreciated.

check your multipliers vcore etc to see if anything has changed in bios that is not compatible w the cpu .my bios does not list lower multis unless i unlock the multis with the wire in the socket trick
your cpu has default multi of 12.0 post your setup in the future,
ram ,bios,vcore,etc, helps to know what you got,dragon lite doesnt seem to like high vcore and ram v at least on my board

ps. try the 2aa5 bios see if it works better i had problems with the 2aa7